They're made up. But that doesn't mean they're not true.

 “But the first bedtime story he ever did read me was Kim.' River could tell she recognised the title, so didn't elaborate. 'After that, well, Conrad, Greene. Somerset Maugham.'
'Ashenden.'
'You get the picture. For my twelfth birthday, he bought me le Carré's collected works. I can still remember what he said about them.'
They're made up. But that doesn't mean they're not true.”
― Mick Herron, Slow Horses